Outline

Objective: To evaluate epileptic phenomenon in patients with intractable epilepsy by gradient magnetic field topography and its movie display.

Methods: The authors have created gradient magnetic field topography and its movie display to recognize the magnetic brain activities. We have used Neuromag system with 102 orthogonal paired planar type gradiometers. Measured data at 102 sensor points were projected onto the surface of patient’s individual brain. Gradient magnetic field topographies were calculated after interpolation among the projected sensors’ points. Furthermore, hundreds or thousands of consecutive topographies were packed as motion picture experts group (MPEG) files. In this way, we can observe the change and spread of biomagnetic activities on the screen of the PC monitor. In addition, we compared the data with those recorded by subdural continuous recording in some cases.

Results: Information provided by this method was very helpful to evaluate epileptic brain activities as compared with conventional EEG and continuous EEG monitoring estimation. It was very interesting and exciting that we can estimate the epileptogenic zone by this method which is recorded during interictal periods.

Conclusions: Using this method, we can evaluate epileptic brain activity visually and topographically in intractable epilepsy patients. In the presentation, we will show the typical case in a movie.